Empathy is a key component of our ability to engage and interact with others. In recent years, the neural mechanisms underlying affective and cognitive empathy have garnered intense interest. This work demonstrates that empathy for others depends upon similar neural mechanisms as when we ourselves experience an empathized-with emotion (e.g., pain). Furthermore, individuals vary markedly in their ability to empathize with others, and this variation depends upon individual differences in neuroanatomy and predicts the tendency to help others. Here, we use a newly developed, high-resolution (800 µm isotropic), quantitative imaging technique to better elucidate the neurobiological mechanisms underpinning individual differences in empathy and neuroanatomy. Our findings replicate and extend previous studies of the neuroanatomical correlates of cognitive and affective empathy; with the latter being associated with the micro-architectural integrity of the insular cortex and the former with the concentration of iron in second somatosensory cortex. These results illustrate novel biomarkers of empathy, suggesting that micro-architectural features of brain areas previously associated with interoceptive and bodily self-awareness are crucial for understanding the mental and emotional states of others. Further, these results may indicate a previously unappreciated neurobiological mechanism underlying socio-economic or stress-related factors in the development of empathy.